Add Task.on_success, .on_retry, .on_failure handlers
Add Task.on_success, .on_retry, .on_failure handlers

mitsuhiko/celery,mitsuhiko/celery,frac/celery,WoLpH/celery,WoLpH/celery,frac/celery,cbrepo/celery,ask/celery,cbrepo/celery,ask/celery